In the regenerator of a fluid catalytic cracking unit, there are frequently placed pipe headers fitted with a plurality of nozzles for the purpose of distributing the regeneration air into the fluidized bed of catalyst. These headers frequently but not necessarily are shaped into a ring configuration and supplied by an inlet header entering the vessel from below as illustrated in U.S. Pat. No. 3,912,460. Rings must be supported and since the ring temperature approaches the process temperature (1,100.degree.-1,400.degree. F.) and shell temperatures are low (200.degree.-400.degree. F.) due to vessel shell internal insulation, supports must be able to compensate for a considerable amount of differential thermal expansion between the ring mechanism, inlet header, shell supporting structure, and ring elongated supporting elements.
In another reactor, U.S. Pat. No. 3,482,946, there is much support structure for the rings to expand, warp, and twist out of shape due to any differential thermal expansion.
While the four support structures disclosed in U.S. Pat. Nos. 2,464,356; 2,554,130; 2,761,639; and 3,606,979 attempt to provide flexibility in their respective mountings, none disclose an elongated support element that may be aligned first in position and then welded in position at both ends as it is held in aligned position and yet provide pivotal movement at both ends of the elongated support element. A principal feature of the disclosed support assembly is the utilization of slip rings that make possible easy alignment prior to welding. None of the above disclosures show such slip rings or methods for assembling them. Another feature of the slip ring-weld connection is that with any thermal expansion or contraction of the elongated support element, supported mechanism, and supporting structure due to operating in the high temperature environment causes pivotal movement of the first slip ring about its pivot pin and pivotal movement of the second slip ring about its pivot pin for preventing undue, intolerable, and unacceptable stresses in the fixed connections.